Cold shrinkable article including a fluoroelastomer composition

ABSTRACT

A tubular cold shrinkable material can include an elastomeric composition including a fluoroelastomer composition, where the elastomeric composition is substantially free of an epichlorohydrin composition. The tubular cold shrinkable material can further include a filler material including a reinforcement-grade carbon black. The tubular cold shrinkable material can further include a peroxide curative.

FIELD

The present invention relates generally to cold shrinkable articles foruse in various applications. In particular, the present inventionrelates to cold shrinkable articles formed from a composition includinga fluoroelastomer.

BACKGROUND

Cold shrinkable articles are used in a variety of different applicationssuch as, for example, splicing together lengths of wire or cable andprotecting, sealing, and/or insulating substrates from adverseenvironmental conditions. Examples of industries that use coldshrinkable articles include the automobile, aerospace, power,telecommunication, chemical, and defense industries.

It is known to form cold shrinkable articles from elastomericcompositions that include an elastomer to facilitate expansion andcontraction of the article. Examples of known elastomers employed incold shrinkable articles include EPDM rubber or silicone rubber. Aproblem in the art has been producing compositions that maintaindesirable elongation-at-break and desirable permanent set properties inhigh temperature conditions.

SUMMARY OF THE INVENTION

Embodiments of the invention include a composition that achievesdesirable elongation-at-break and desirable permanent set properties inhigh temperature conditions.

For example, embodiments can include an article of manufacture includinga tubular cold shrinkable material. The tubular cold shrinkable materialcan include an elastomeric composition including a fluoroelastomercomposition, where the elastomeric composition is substantially free ofan epichlorohydrin composition. Also, the tubular cold shrinkablematerial can further include a filler material including areinforcement-grade carbon black. Also, the tubular cold shrinkablematerial can further include a peroxide curative.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a cold shrinkable article of the presentinvention in a relaxed state, prior to expansion.

FIG. 2 is a perspective view of the cold shrinkable article of FIG. 1 inan expanded state on a core.

FIG. 3 is a perspective view of the cold shrinkable article of FIG. 1 inan expanded state on the core of FIG. 2, with an associated substrate.

FIG. 4 is a perspective view of the cold shrinkable article of FIG. 1partially located on the core of FIG. 2 and partially deployed on thesubstrate of FIG. 3.

FIG. 5 is a perspective view of the cold shrinkable article of FIG. 1including indicia and fully deployed on the substrate of FIG. 3.

FIG. 6 is a perspective view of a branched cold shrinkable article ofthe present invention in a relaxed state prior to expansion.

FIG. 7 is a perspective view of the branched cold shrinkable article ofFIG. 6 in an expanded state on a plurality of cores.

FIG. 8 is a perspective view of a corrugated cold shrinkable article ofthe present invention.

DETAILED DESCRIPTION

The present invention relates to an article of manufacture including atubular cold shrinkable material formed from an elastomeric material.The term “cold shrinkable”, as used herein, is defined as the capabilityof an article (or a portion of an article) to shrink from an expandedstate toward a relaxed or a partially expanded state.

Elastomers can be included in the compositions of cold shrinkablearticles to allow the cold shrinkable articles to expand from a relaxedstate to an expanded state, while also allowing the articles to coldshrink back toward the relaxed state. In embodiments of the invention,for example, the elastomeric composition can include a fluoroelastomercomposition, and the elastomeric composition can be free from anyepichlorohydrin composition.

Unless otherwise stated, all concentrations herein are expressed inparts by weight per hundred parts by weight rubber (phr), with therubber defined to be the total weight of the fluoroelastomer. Thus, asused herein, the phr of a particular component represents the parts byweight of the component relative to 100 total parts by weight offluoroelastomer.

Some examples of suitable fluoroelastomers for use in the elastomericcompositions of the present invention include fluorinated elastomericcopolymers (i.e., polymers derived from two or more different monomers),fluorinated elastomeric terpolymers (i.e., polymers derived from threedifferent monomers) and fluorinated elastomeric polymers including morethan three different monomers. Some examples of suitable fluorinatedelastomeric copolymers include copolymers of vinylidene fluoride,tetrafluoroethylene, and hexafluoropropylene (e.g., the DAI-EL G-801product and the DAI-EL G-802 product, both commercially available fromDaikin Industries of Osaka, Japan) and copolymers of vinylidene fluorideand tetrafluoroethane-perfluoro(methyl vinyl ether) (e.g., the VTR 8500product or VTR 8650 product, both commercially available from Dupont-DowElastomer of Wilmington, Del.). Examples of suitable fluorinatedelastomeric terpolymers include terpolymers of tetrafluoroethylene,hexafluoropropylene and vinylidene fluoride. In some embodiments, thefluoroelastomer may be modified with iodine or another material tofacilitate cross-linking of the fluoroelastomer.

Besides fluoroelastomer, the elastomeric compositions of the presentinvention may also include additional optional materials such asreinforcement-grade (reinforcing) filler materials, fluoroplastics inaddition to fluoroelastomers, pigments, energy-beam absorbents,antioxidants, stabilizing agents, fillers, oils, processing aids,neutralizers, rheology modifiers, silane coupling agents, cross-linkingmaterials (e.g., cross-linking agents, cross-linking co-agents, and cureaccelerators), lubricants, flame retardants, flame retardant synergists,antimicrobials, any other additive known in the art, and any combinationof these in any proportion. The concentration of these additionalmaterials in the elastomeric composition of the present invention may beany concentration sufficient to provide a desired result.

Reinforcement-grade (reinforcing) filler material may optionally beincluded in the elastomeric composition of the present invention toenhance the split and tear properties of cold shrinkable articles(formed from the elastomeric composition) at elevated temperatures.Examples of suitable filler materials include silica-based reinforcementfiller, reinforcement-grade carbon black, fluoroplastics, clays, and anycombination of any of these in any proportions.

As used herein, the term “silica-based reinforcement filler” is definedto include all compounds of the formula SiO₂ (e.g., pure silica); allcompositions that include at least about ten weight percent of SiO₂and/or an SiO₂ derivative, based upon the total weight of thecomposition; all silicates; and any combination of any of these in anyproportion. Examples of suitable silica-based reinforcement fillersinclude silica (also referred to as silicon dioxide); silane-treatedsilica; fumed silica (e.g., such as the CABOSIL® M-5 productcommercially from Cabot Corporation of Billerica, A); silane-treatedfumed silica such as, for example, the AEROSIL® R972 product, theAEROSIL® R974 product, and the AEROSIL® 200 product that are allcommercially available from Degussa Company of Parsippany, N.J. and theCABOSIL® line of silane-treated fumed silica products commercially fromCabot Corporation of Billerica, Mass.; silicates; and any combination ofany of these in any proportion. Examples of suitable silicates includecalcium silicate, aluminum silicate, and mixtures of these. In someembodiments, the average particle size of the silica-based reinforcementfiller may be less than about 30 nanometers (nm). In other embodiments,the average particle size of the silica-based reinforcement filler maybe as low as about 10 nm and as high as about 20 nm.

The phrase “reinforcement-grade carbon black” as used herein, includesany carbon black with an average particle size smaller than about 40 nm,which corresponds to an average surface area of about 65 m²/g. Someparticularly suitable average particle sizes for reinforcement-gradecarbon black range from about 9 nm to about 40 nm. Carbon black that isnot reinforcement grade include carbon black with an average particlesize larger than about 40 nm. As shown in Table 1, some examples ofsuitable reinforcement-grade carbon black include, for example, N-100series carbon black, N-200 series carbon black, and N-300 series carbonblack, which are all commercially available from Cabot Corporation ofBillerica, Mass.

TABLE 1 Particle ASTM Size Name Abbrev. Desig. nm Super Abrasion FurnaceSAF N110 20-25 Intermediate SAF ISAF N220 24-33 High Abrasion FurnaceHAF N330 28-36 Easy Processing EPC N300 30-35 Channel Fast ExtrudingFurnace FEF N550 39-55 High Modulus Furnace HMF N683 49-73Semi-Reinforcing SRF N770 70-96 Furnace Fine Thermal FT N880 180-200Medium Thermal MT N990 250-350

Elastomers including a filler material of reinforcement-grade carbonblack can offer improved tensile strength, improved modulus, greaterstiffness, and increased resistance to abrasive wear. On the other hand,elastomers including a carbon black filler material that is notreinforcement-grade may not exhibit the enhanced properties orcharacteristics that are exhibited by reinforcement-grade carbon blacks,as illustrated in the Examples corresponding to Tables 2-4. Embodimentsof the present invention demonstrate that reinforcement-grade carbonblack offers advantageous mechanical properties when utilized withfluoroelastomers at both room temperature and elevated temperatures, asillustrated in the Examples corresponding to Tables 2-4.

Examples of fluoroplastics that may serve as (or as part of) thereinforcement-grade (reinforcing) filler material include homopolymersof tetrafluoroethylene monomers, any copolymer that includes atetrafluoroethylene monomer, any terpolymer that includes atetrafluoroethylene monomer, any other polymer that includes atetrafluoroethylene monomer and three or more different monomers, andany combination of any of these in any proportion. Examples of suitablecopolymers include copolymers of tetrafluoroethylene andhexafluoropropylene (e.g., the ZONYL® MP 1500 product commerciallyavailable from DuPont Fluoroproducts of Wilmington, Del.).

Examples of suitable clay fillers that may serve as (or as part of) thereinforcement-grade (reinforcing) filler material include silane-treatedkaolin clay (aluminum silicate) fillers commercially available fromEngelhard Corporation of Iselin, N.J. under the trade designations“Translink 37”, “Translink 77”, “Translink 445”, “Translink 555”, and“Translink HF-900”.

In some embodiments of the invention, the concentration of the fillermaterial can be in the range of about 10 phr to about 25 phr. Forexample, if the filler materials include only a fumed silica, the fumedsilica can be in the range of about 10 phr to about 25 phr. Also, forexample, if the filler materials include only a reinforcement-gradecarbon black, the reinforcement-grade carbon black can be in the rangeof about 10 phr to about 25 phr. Also, for example, if the fillermaterials include both a fumed silica and a reinforcement-grade carbonblack, the concentration of the combination of filler materials can bein the range of about 10 phr to about 25 phr.

The elastomeric composition of the cold shrinkable material can alsoinclude an energy beam absorbent. The energy beam absorbent can providefor an energy beam induced indicia charred on an external surface of thecold shrinkable material responsive to application of a focused energybeam on the energy beam absorbent. Examples of suitable energy beamabsorbents for use in the elastomeric compositions of the presentinvention include PolyOne Material No. AD 3000051160 (“Stan-ToneMB-27838 Black”), PolyOne Material Product No. CC10041306WE, and“Stan-Tone MB-29293” (all available from PolyOne Corporation of Suwanee,Ga.); RTP Material No. RTP 0299×102892 SSL-801191, available from RTPCompany of Winona, Minn.; Clariant Material No. 00025275, available fromClariant Masterbatches Division of Albion, Mich.; Ticona Material No.1000-2LM ND3650, available from Ticona of Summit, N.J.; BASF MaterialNo. NPP TN020327 (“Ultramid B3K LS Black 23189”), available from BASFCorporation Performance Polymers of Mt. Olive, N.J.; and combinationsthereof. These energy beam absorbent materials may include titaniumdioxide, mica, and combinations thereof. Titanium dioxide may functionas both a pigment and an energy beam absorbent, as discussed inBirmingham, Jr. et al., U.S. Pat. No. 5,560,845.

The elastomeric compositions of the present invention may include apigment or combination of pigments to affect a base color of coldshrinkable articles formed from the elastomeric compositions of thepresent invention. Examples of suitable pigments include titaniumdioxide; carbon black; zinc oxide; pression blue; cadimum sulfide; ironoxide; chromates of lead, zinc, barium, and calcium; azo; thioindigo;anthraquinone; anthoanthrone; triphenonedioxazine; fat dye pigments;phthalocyanine pigments, such as copper phthalocyanine pigment and itsderivatives; quinacridon pigment; pigments commercially available underthe trade designations “Cinquasia”, “Cromophtal”, “Filamid”, “Filester”,“Filofin”, “Homachrome”, “Horna Molybdate”, “Hornatherm”, “Irgacolor”,“Irgalite”, “Irgasperse”, “Irgazin”, “Micranyl”, “Microlen”,“Microlith”, “Microsol”, and “Unisperse”, all from Ciba SpecialtyChemicals of Tarrytown, N.Y.; and any combination of any these in anyproportion. In some embodiments, the color and concentration ofpigment(s) incorporated within the elastomeric composition may dependupon how much energy beam absorbent is incorporated. As one example, ayellow-color pigment may be used in combination with an energy beamabsorbent to yield cold shrinkable articles that, when exposed to afocused energy beam, exhibit high-contrast energy-beam induced indicia.

Examples of suitable antioxidants for use in the elastomericcompositions of the present invention include solutions of zinc2-mercaptotoluimidazole in petroleum process oil (e.g., “Vanox ZMTI” and“Vanox MTI” commercially available from R.T. Vanderbilt Company, Inc. ofNorwalk, Conn.); mixtures of octylated diphenylamines (e.g. “AgeriteStalite” commercially available from R.T. Vanderbilt Company, Inc. ofNorwalk, Conn.); phenolic-based antioxidants (e.g., IRGANOX® 1010commercially available from Ciba Specialty Chemicals); aromatic aminetype antioxidants (e.g., NAUGARD® 445 commercially available fromCrompton Corporation of Middlebury, Conn.); and combinations of these.

Examples of oils that may suitably be included in elastomericcompositions of the present invention include hydrocarbon oils (e.g.polychlorotrifluorethylene) commercially available from HalocarbonProduction Corporation of River Edge, N.J. under the trade designationHalocarbon 95).

Examples of some suitable cross-linking agents for the elastomericcompositions include amines and peroxides, including peroxide curatives,such as the following peroxides that are commercially available fromR.T. Vanderbilt Company, Inc. of Norwalk, Conn.: dicumyl peroxide (e.g.,the VAROX® DCP product, the VAROX® DCP-40C product, the VAROX® DCP-40KEproduct, and the VAROX® DCP-40KE-HP product); benzoyl peroxide (e.g.,the VAROX® ANS product); dibenzoyl peroxide (e.g., the VAROX® A 75product); 2,5-dimethyl-2,5-di(t-butylperoxy) hexane (e.g., the VAROX®DBPH product, the VAROX® (DBPH 40 MB product, the VAROX® DBPH-50product, the VAROX® DBPH-50-HP product, the VAROX® DBPH-P20 product, andthe VAROX® DCP-40KE product), t-butyl perbenzoate (e.g., the VAROX® TBPBproduct and the VAROX® TBPB-50 product);2,5-dimethyl-2,5-di(t-butylperoxy) hexyne-3 (e.g., the VAROX® 130product and the VAROX® 130-XL product); alpha,alpha-bis(t-butylperoxy)diisopropylbenzene (e.g., the VAROX® VC-Rproduct); di-(2-tert-butylperoxyisopropyl) benzene (e.g., the VAROX®802-40C product, the VAROX® 802-40KE product, and the VAROX® 802-40KE-HPproduct); di-(2-tert-butylperoxyisopropyl) benzene in EPR (e.g., theVAROX® 802-40 MB product); derivatives of any of these; and anycombination of these in any proportion. Examples of suitablecross-linking agent concentrations in the elastomeric compositions, suchas for example Varox peroxide curative, range from as low as about 1 phrto as high as about 6 phr.

Cross-linking co-agents may be incorporated in the elastomericcompositions of the present invention to enhance the cross-linkingreaction. Examples of suitable cross-linking co-agents for incorporationin the elastomeric compositions include triallyl isocyanurates (e.g.,the TAIC DLC-A product commercially available from Natrochem Inc. ofSavannah, Ga.) and acrylic co-agents. Examples of suitable acrylicco-agents include multi-functional monomers, such as difunctional andtrifunctional monomers. Examples of suitable difunctional monomersinclude the following, which are commercially available from SartomerCompany, Inc., Exton, Pa.: 1,3-butylene glycol diacrylate, 1,3-butyleneglycol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanedioldimethacrylate, 1,6 hexanediol diacrylate, 1,6 hexanedioldimethacrylate, aliphatic dimethacrylate monomer, alkoxylated aliphaticdiacrylate, alkoxylated cyclohexane dimethanol diacrylate, alkoxylatedcyclohexane dimethanol diacrylate, alkoxylated cyclohexane dimethanoldiacrylate, alkoxylated hexanediol diacrylate, alkoxylated hexanedioldiacrylate, alkoxylated hexanediol diacrylate, alkoxylated neopentylglycol diacrylate, alkoxylated neopentyl glycol diacrylate, aromaticdimethacrylate monomer, caprolactione modified neopentylglycolhydroxypivalate diacrylate, caprolactone modified neopentylglycolhydroxypivalate diacrylate, cyclohexane dimethanol diacrylate,cyclohexane dimethanol dimethacrylate, diethylene glycol diacrylate,diethylene glycol dimethacrylate, dipropylene glycol diacrylate,ethoxylated (10) bisphenol alpha diacrylate, ethoxylated (2) bisphenolalpha dimethacrylate, ethoxylated (3) bisphenol alpha diacrylate,ethoxylated (30) bisphenol alpha diacrylate, ethoxylated (30) bisphenolalpha dimethacrylate, ethoxylated (4) bisphenol alpha diacrylate,ethoxylated (4) bisphenol alpha dimethacrylate, ethoxylated (8)bisphenol alpha dimethacrylate, ethoxylated bisphenol alphadimethacrylate, ethoxylated bisphenol alpha dimethacrylate, ethoxylated(10) bisphenol dimethacrylate, ethoxylated (6) bisphenol alphadimethacrylate, ethylene glycol dimethacrylate, hydroxypivalaldehydemodified trimethylolpropane diacrylate, neopentyl glycol diacrylate,neopentyl glycol dimethacrylate, polyethylene glycol (200) diacrylate,polyethylene glycol (400) diacrylate, polyethylene glycol (400)dimethacrylate, polyethylene glycol (600) diacrylate, polyethyleneglycol (600) dimethacrylate, polyethylene glycol dimethacrylate,polypropylene glycol (400) dimethacrylate, propoxylated (2) neopentylglycol diacrylate, tetraethylene glycol diacrylate, tetraethylene glycoldimethacrylate, tricyclodecane dimethanol diacrylate, triethylene glycoldiacrylate, triethylene glycol dimethacrylate, tripropylene glycoldiacrylate, tripropylene glycol diacrylate, and combinations thereof.Examples of suitable trifunctional monomers include trimethylolpropanetrimethacrylate, trimethyolpropane triacrylate, and combinationsthereof. Examples of suitable cross-linking co-agent concentrations inthe elastomeric compositions of the present invention range from as lowas about 0.5 phr and as high as about 4.5 phr, on a weight basis.

The elastomeric composition of the cold shrinkable material can beprepared by blending the components of the elastomeric composition,including the fluoroelastomer, in an appropriate mixing apparatus. Forexample, the components of the elastomeric composition may generally becombined in any order in an appropriate mixing apparatus at a componenttemperature of about 60° C.

Additional optional materials may also be included with thefluoroelastomer prior to mixing. If cross-linking agents orcross-linking co-agents are to be incorporated in the elastomericcomposition, the components including the fluorelastomer may be blendedtogether in a first mixing step as described above. The cross-linkingagents and/or cross-linking co-agents may then be blended into theelastomeric composition in a second mixing step at a lower temperaturethan the first mixing temperature, such as between about 50° C. andabout 100° C., to prevent premature cross-linking.

The elastomeric composition may then be formed into a cold-shrinkarticle by any suitable process such as, for example, extrusion ormolding. In some embodiments, the elastomeric composition of thecold-shrink article is cured, using a suitable curing process, to affectcross-linking of the elastomeric composition. Some examples of suitablecuring processes include, for example, elevated temperature and pressureconditions (e.g., autoclaving), irradiation, or any other suitablecuring process known in the art.

In some embodiments, the cold-shrink article may be autoclaved in anoxygen-free and/or water-free atmosphere, with the oxygen-free and/orwater-free atmosphere being used in place of steam. As used herein,unless otherwise stated, the term “oxygen-free atmosphere” refers to anatmosphere of a set volume of gas that includes less than about onevolume percent oxygen, based on the total volume of the gas in theatmosphere, and the term “water-free atmosphere” refers to an atmosphereof a set volume of gas that includes less than about 0.1 volume percentwater vapor, based on the total volume of the gas in the atmosphere.Examples of oxygen free-atmospheres include atmospheres includinggreater than about 99% by volume of nitrogen gas, argon gas, helium gas,xenon gas, neon gas, any other suitable inert gas, and combinations ofany of these in any proportion. For example, tubing of the presentinvention may be autoclave-cured in a mold. As used herein, the term“tubing” refers to a hollow cylinder open on both ends. In oneembodiment, the tubing is first formed (e.g., by extrusion) and thenplaced inside spiral grooves of an aluminum mold. The mold is placed ina heated press and subjected to a temperature of about 185° C. and apressure ranging from about 5-14 megapascals (Mpa) (about 75-200 psi).One end of the tubing is connected to a pressurized nitrogen gas supplycontaining about 99.5% nitrogen gas by volume. The mold may be purgedfor about two minutes with the pressurized nitrogen gas supply at a flowrate of about 40 cubic ft of the pressurized nitrogen gas. Any otherpurge time and flow rate sufficient to reduce oxygen and/or moisture toacceptable levels may also be used. After the initial purging, the moldis sealed off, and the pressure inside the mold may be maintained atabout 200 pounds per square inch (psi) for about 20 minutes. The mold isthen released and the pressure in the mold is allowed to return toatmospheric pressure. The tubing may then be removed from the mold andcooled.

The elastomeric compositions of the present invention may be formed intocold shrinkable articles of any shape or geometric configuration knownin the art. Some non-exhaustive examples of cold shrinkable articlesinclude tubing, plaques, and multiple-branched structures (i.e.,tube-like structures with multiple entrances and/or exits).

Cold shrinkable articles formed from elastomeric compositions of thepresent invention may exhibit various advantageous mechanical propertiesin various combinations under various environmental conditions (e.g.,room temperature or 150° C.). The cold shrinkable material formed fromthe elastomeric composition exhibit improved elongation, permanent set,and tear properties while in expanded states at elevated temperatures.Some embodiments of cold shrinkable articles of the present inventionmay be exposed, in an expanded state, to temperatures of at least about150° C. for an extended period of time without exhibiting, upon unaidedvisual inspection by a human eye, any splitting, tearing, or breakage.

For example, in some embodiments, a cold shrinkable material can includean elastomeric composition including a fluoroelastomer, and thefluoroelastomer is mixed with a reinforcement-grade carbon black, afumed silica, and a peroxide curative. After the entire processing ofthe elastomeric article is completed, including the proper peroxidecuring process, the resultant elastomeric composition can exhibitadvantageous properties, in particular, for cold shrink materials.

In some embodiments, a proper weight percent of reinforcement-gradecarbon black, fumed silica, and peroxide curative should be maintainedto establish desirable elongation-at-break properties and desirablepermanent set properties even while experiencing high temperatureconditions. For example, too high a percentage of peroxide may result inundesirably high permanent set properties, and too low a percentage ofperoxide may result in undesirably low elongation properties. Also forexample, too high a percentage of carbon black and/or silica fillermaterial may result in undesirably low elongation properties, and toolow a percentage of carbon black and/or silica filler material mayresult in undesirable performance in high temperature conditions.Therefore, in some embodiments, the quantity of the filler material(carbon black and/or silica) is in the range of about 10 phr to about 25phr, and the quantity of peroxide curative is in the range of about 1phr to about 6 phr. Such a combination results in advantageousproperties of elongation greater than about 500% and permanent set lessthan about 25% at room temperature; elongation greater than about 450%and permanent set less than about 25% at 130 degrees Celsius; andelongation greater than about 400% and permanent set less than about 25%at 150 degrees Celsius. Additionally, such a combination results in acold shrinkable material which does not tear while being held for sevendays in a 200% radially expanded state at 150 degrees Celsius.

Also, various embodiments of the cold shrinkable articles of the presentinvention exhibit chemical resistance to substances such as, forexample, diesel fuel and hydraulic fluid. Some embodiments of the coldshrinkable articles of the present invention exhibit a percent weightincrease of less than about 25% when immersed in diesel fuel at about49° C. for 24 hours and/or a percent weight increase of less than about10% when immersed in hydraulic fluid at about 71° C. for 24 hours.

In reference to the Figures, a tubular cold shrinkable article 10 of thepresent invention is depicted in FIG. 1 in an initial relaxed stateprior to any expansion. The cold shrinkable article 10 includes a radialwall 11, an inner surface 14, and an outer surface 16.

When cold shrinkable article 10 is in the initial relaxed state, theradial wall 11 has a longitudinal length A, an inner diameter B, anouter diameter C, and a layer thickness D. The longitudinal length A andthe inner diameter B may vary based upon individual needs of a givenapplication, such as for example, the dimensions of a substrate aboutwhich the cold shrinkable article 10 will be placed. The outer diameterC is generally determined by the inner diameter B and the layerthickness D, where the layer thickness D is ordinarily substantiallyuniform both around a circumference E and along the length A of the coldshrinkable article 10. The layer thickness D is desirably thin enough toallow the cold shrinkable article 10 to readily expand from the initialrelaxed state upon application of expansion forces.

Examples of suitable layer thickness D range from as low as about 0.060inches to as high as about 0.25 inches. Examples of suitable innerdiameter B range from as low as about 0.2 inches to as high as about 3inches.

Various stages of a method for deploying the cold shrinkable article 10are depicted in FIGS. 2-5. The tubular cold shrinkable material 10 canbe disposed on a removable core 18. The removable core 18 supports thecold shrinkable material 10 in an expanded state. The cold shrinkablearticle 10 is depicted in an expanded state on the removable core 18 inFIG. 2. A substrate 20 is shown in FIG. 3 to be inserted into the core18, which supports the expanded form of the cold shrinkable article 10.The cold shrinkable article 10 partially deployed from the core 18 ontothe substrate 20 is depicted in FIG. 4. The cold shrinkable article 10fully deployed on the substrate 20 is depicted in FIG. 5. The coldshrinkable article 10 may protect substrate 20 and/or may identify thesubstrate 20, which may, for example, comprise a wire, a cable, afluid-carrying pipe, or a conduit.

To deploy the cold shrinkable article 10 on the substrate 20, the coldshrinkable article 10 is first cross-sectionally (or radially) expandedfrom the initial relaxed state to the expanded state and oriented on thecore 18, as depicted in FIG. 2. As used herein, the terms “expanded”,“expansion”, “expanded state”, and the like, refer to a cross-sectionalexpansion that increases inner diameter B and outer diameter C, asopposed to a longitudinal expansion that increases longitudinal lengthA, though such a longitudinal expansion is permissible. The coldshrinkable article 10 may be expanded and placed onto the core 18 in anyconventional manner. The core 18 may generally have any structure thatis suitable for retaining the cold shrinkable article 10 in the expandedstate. For example, the core 18 may be a rigid, hollow, plastic tube.

When the cold shrinkable article 10 is in the expanded state, as bestdepicted in FIG. 2, the radial wall 11 has a longitudinal length A′, aninner diameter B′, an outer diameter C′, and a wall thickness D′. Due tothe expansion, the inner diameter B′ and the outer diameter C′ arelarger than the inner diameter B and the outer diameter C, respectively.Suitable expansion of the cold shrinkable article 10 may generally rangefrom about 150% to about 400%, where the expansion is characterized interms of the percent expansion of the inner diameter B relative to theinner diameter B′. Particularly suitable expansion of the coldshrinkable article 10 may generally range from about 200% to about 300%.

The substrate 20 may be inserted within the core 18 holding the expandedform of the cold shrinkable article 10, as depicted in FIG. 3. In someembodiments, the substrate 20 may be centered within the hollow portionof the core 18 using guide fingers (not shown) contained within the core18. After the substrate 20 is inserted within the core 18, the coldshrinkable article 10 is conveyed from the core 18 onto the substrate20, as depicted in FIG. 4. The conveyance may be accomplished in avariety of manners, such as by sliding the cold shrinkable article 10from the core 18 onto the substrate 20, or by collapsing and removingthe core 18 and thereby allowing the cold shrinkable article 10 toencompass and come into engagement with the substrate 20.

When the cold shrinkable article 10 is removed from the core 18, thecold shrinkable article 10 cold shrinkables from the expanded statetoward (but not necessarily all the way to) the initial relaxed state.Whether or not the cold shrinkable article 10 reaches the relaxed statedepends on the diameter of the substrate 20. The substrate 20 may have adiameter that allows the cold shrinkable article 10 to substantiallyreturn to the initial relaxed state and substantially regain the innerdiameter B and the outer diameter C, as best depicted in FIG. 4. Theinner diameter B of cold shrinkable article 10 in the initial relaxedstate may be slightly smaller than the exterior diameter of thesubstrate 20, which prevents the cold shrinkable article 10 from fullyshrinking back to the initial relaxed state, and thereby provides a snugand secure fit and engagement of the cold shrinkable article 10 ontoperipheral surfaces of the substrate 20. When the cold shrinkablearticle 10 is fully deployed on the substrate 20, the inner surface 14of the cold shrinkable article 10 extends around, faces, and istypically in contact with the outer surface 22 of the substrate 20, asshown in FIG. 5.

In some embodiments, the outer surface 16 of the cold shrinkable article10 may include identifiers in the form of optional indicia 24, which mayprovide, for example, information relating to the cold shrinkablearticle 10 and/or the substrate 20. The indicia 24 may be a single markor a plurality of marks, and may include a variety of textual (i.e.,alphanumeric) or graphical characters, symbols, and the like. Theindicia 24 may also be or include machine-readable indicia, such as barcodes. Also, the indicia 24 may have a surface texture that is differentfrom the texture of portions of the outer surface 16 other than theindicia 24.

The indicia 24 may be formed using any suitable process including, forexample, ink application to the outer surface 16 and/or focused energybeam marking of the outer surface 16. A focused energy beam refers to adirectionally focused stimulated emission of radiation, such as a laserbeam, to produce a charring indicia on the external surface of the coldshrinkable material. The indicia 24, in the form of energy-beam inducedindicia, may be formed, for example, by expanding the cold shrinkablearticle 10 from the initial relaxed state, marking the outer surface 16by application of energy from a focused energy beam, and allowing thecold shrinkable article 10 to cold shrinkable back toward the initialrelaxed state.

To facilitate formation of energy-beam induced indicia, the elastomericcompositions of the present invention may include an energy beamabsorbent. Such energy beam absorbents, upon heating by a focused energybeam, may be employed to provide the indicia 24 with a different colorthan the color of the outer surface 16 other than the indicia. In thisway, the color of the indicia 24 may contrast with the color of theouter surface 16 so the indicia are prominent and legible. If a highvisual legibility of the indicia 24 is desired, both a pigment and anenergy beam absorbent may be included in the elastomeric composition toprovide a high contrast between the base color of the outer surface 16and the contrasting color of the indicia 24. For further discussionregarding energy-beam induced identifiers and methods for marking coldshrinkable articles, see Publication No. US 2005/0214491 A1 published onSept. 29, 2005, and entitled “Cold-Shrink Marker Sleeve.”

In some embodiments, indicia 24 are legible to an unaided eye of anindividual with 20/20 vision located at least about 36 centimeters awayfrom indicia 24 when the cold shrinkable article 10 is in an expandedstate or a relaxed state.

Information pertaining to the cold shrinkable article 10 and/or thesubstrate 20 may also be conveyed to a user by a base color of the outersurface 16 of the cold shrinkable article 10. For example, a blue basecolor of the outer surface 16 may convey different information to a userthan a yellow or black base color. In some embodiments, the coldshrinkable article 10 may include both the indicia 24 and aninformation-conveying base color of the outer surface 16.

Cold shrinkable articles of the present invention may include aplurality of elastomeric members. A branched cold shrinkable article 30of the present invention, in a relaxed state prior to expansion, isdepicted in FIG. 6. The cold shrinkable article 30 may include aplurality of hollow elastomeric portions (or members) 32A, 32B, 32C, and32D that each have the inner surface 14 and the outer surface 16. Therespective inner surfaces 14 define elongate cavities (not shown)through each of the elastomeric portions 32A, 32B, 32C, and 32D that arein communication with each other.

When the hollow elastomeric portions 32A, 32B, 32C, and 32D arestretched to the expanded state, cores 18 may be inserted within theexpanded portions 32A, 32B, 32C, and 32D, as depicted in FIG. 7, tomaintain the portions 32A, 32B, 32C, and 32D in the expanded state. Thecold shrinkable article 30 (portions 32A, 32B, 32C, and 32D) may bedeployed on one or more substrates 20 from the expanded states on thecores 18 pursuant to the methods described above in relation todeployment of the cold shrinkable article 10.

Cold shrinkable articles of the present invention may includecorrugations that allow the cold shrinkable articles to exhibit alongitudinal length in a non-corrugated relaxed state that issubstantially longer than the longitudinal length of the cold shrinkablearticles when positioned on a removable core in an expanded, corrugatedstate. A cold shrinkable article 40, which is partially deployed fromthe core 18 onto the outer surface 22 of the substrate 20, is depictedin FIG. 8. When in the expanded state on the core 18, the coldshrinkable article 40 includes a multitude of corrugations 42. Asillustrated by the cold-shrunk portion 44, after release from the core18, unsupported corrugated portions of the cold shrinkable article 40extend longitudinally and the corrugations formerly present in theunsupported portions effectively disappear as the cold-shrunk portion 44approaches the initial relaxed state.

Property Analysis and Characterization Procedures

Various analytical techniques may be used to characterize the propertiesof cold shrinkable articles of the present invention. Details aboutthese analytical techniques follow. As used herein, “ASTM D412” refersto ASTM D412-98a (Reapproved 2002) entitled “Standard Test Methods forVulcanized Rubber and Thermoplastic Elastomers—Tension”, which waspublished in January 2003 and is available from the American Society forTesting and Materials International of West Conshohocken, Pa.

I. Mechanical Property Tests

A. Elongation at Break and Stress at Break

Determinations of the stress at break and percent elongation at breakfor dumbbells formed from the elastomeric compositions of the presentinvention are performed pursuant to the procedures of Test Method A ofASTM D412 using a tensiTECH III tensile tester commercially availablefrom Tech Pro of Cuyahoga Falls, Ohio.

A method described below similar to Test Method B of ASTM D412 may beused to determine the elongation at break for ring samples cut fromtubing formed from elastomeric compositions of the present invention.According to the method employed herein, ring samples, having alongitudinal width of about ⅜ of an inch, are cut from the tubing, andthe ring samples are placed in a tensile testing apparatus. Each end ofeach ring sample is secured to a jaw between two 0.124 inch-diameterpins attached to each jaw. The jaws of the tensile tester apparatus arethen pulled in opposite directions at a rate of about 20 inches/minuteand the strain and break loads are recorded. Unless otherwise statedherein, the elongation at break and stress at break tests are performedin a temperature-controlled box at a temperature of about 150° C., withthe test samples conditioned for about 6±2 minutes at 150° C. beforeconducting the tests.

The stress at break for the ring samples is computed using the followingequation:

${{Actual}\mspace{14mu}{Stress}} = {\frac{{Break}\mspace{14mu}{Load}}{( {2 \times {Width}\mspace{14mu}{of}\mspace{14mu}{Ring}\mspace{14mu}{Sample} \times {Thickness}\mspace{14mu}{of}\mspace{14mu}{Ring}\mspace{14mu}{Sample}} )}.}$

The elongation at break for the ring samples is computed using thefollowing equation:Actual Elongation of ID at break=((Stretched circumference−Initialcircumference)/(Initial circumference))×100.

B. Percent Permanent Set

The percent permanent set test illustrates the amount of elasticrecovery an article exhibits. The percent permanent set is calculatedusing the following equation:

${\%\mspace{14mu}{PermanentSet}} = \frac{100 \times ( {{RelaxedLength} - {OriginalLength}} )}{( {{TestLength} - {OriginalLength}} )}$

To determine the percent permanent set for plaques, dumbbell testspecimens are cut from plaques pursuant to the procedures of Test MethodA of ASTM D-412. Parallel bench marks separated by a distance of an inchare placed at the approximate center of each dumbell. The dumbbells areplaced in a set fixture and stretched until the distance between thebench marks equals 2 inches, which correlates to 100% strain. The loadedset fixture is then placed in a 100° C. oven for 3 hours. After 3 hours,the fixtures are removed from the oven and the stretched dumbbells areallowed to cool at room temperature (21° C.±2° C.) for 1 hour. Thestretched dumbbells are removed from the set fixture and placed on asmooth wooden or cardboard surface. The distance between the parallelbench marks is measured after waiting 30±2 minutes. The percentpermanent set is determined using the formula provided above with theoriginal length equaling 1 inch, the test length equaling 2 inches, andthe relaxed length equaling the final distance between the bench marksafter cooling.

To determine the percent permanent set for tubing, ring samples having alength of ⅜ of an inch are cut from the tubing and the initial diametersof the ring samples are measured. The ring samples are then insertedover a steel mandrel having a diameter about twice the internal diameterof the tubing ring samples, which causes the ring samples to radiallystretch about 100% in diameter. An end of the mandrel is equipped with aconical shape to facilitate inserting & removing the mandrel from thering samples. While stretched on the mandrel, the ring samples areplaced in a 100° C. oven for 3 hours. After expiration of the 3-hourperiod, the mandrel and stretched ring samples are removed from the ovenand allowed to cool at room temperature (21° C.±2° C.) for 1 hour. Thering samples are then removed from the mandrel and placed on a smoothwooden or cardboard surface. The internal diameters of the ring samplesare measured after passage of 30±2 minutes, and the following formula isused to compute the percent permanent set of the ring samples:

${{\%\mspace{14mu}{Permanent}\mspace{14mu}{Set}} = \frac{100( {{r\; d} - {od}} )}{{md} - {od}}},$where rd is the relaxed diameter, od is the original diameter, and md isthe mandrel diameter.

C. Tubing Split Test

Tubing split tests are conducted to illustrate the tear properties ofthe cold shrinkable articles over time. The test is conducted usingtubing samples prepared from elastomeric compositions of the presentinvention pursuant to the methods described above. Samples of tubinghaving a length of about 3 to 4 inches are cut and placed over steelmandrels, which have a diameter about three times the internal diameterof the tubing samples. As such, the tubing samples are expanded radiallyby about 200%. While retained in a state of about 200% radial expansion,the samples are placed in a 150° C. oven for seven days. Afterexpiration of the seven-day period, the elongated samples are visuallyinspected for signs of tearing. Tubing samples are deemed to have failedthe split test if any tearing or splitting is visually observed by anunaided human eye.

II. Fluid Resistance Tests

The fluid resistance of cold shrinkable articles of the presentinvention is determined by cutting dumbbell test specimens (pursuant tothe methods of Test Method A of ASTM D412) from plaques formed fromcompositions of the present invention. The test specimens are weighedindividually and then immersed in either hydraulic fluid or diesel fuelin wide test tubes. The test tubes containing the diesel fuel are placedin an oil bath maintained at a temperature of about 49° C. for 24 hoursand the test tubes containing the hydraulic fluid were placed in an oilbath maintained at a temperature of about 71° C. for 24 hours. The testspecimens are then removed from test tubes, padded dry with filterpaper, and weighed individually. The respective percent absorptions ofdiesel fuel and hydraulic fluid for the test specimens are then computedusing the initial weights and the final weights of the dumbbell testspecimens.

III. Laser Marking Test

The visual legibility of the indicia is qualitatively determined forcold shrinkable articles pursuant to the following procedure. Tubingwithout indicia, having a 1.0 mm outer diameter, is expanded onto a corewith a 2.0 cm diameter. The expanded tubing is then laser marked to formindicia by a Nd:YAG laser system. The Nd:YAG laser system iscommercially availably under the trade name “Hi-Mark” No. 400 from GSILumonics, Inc. of Kanata, Ontario, Canada. The laser settings for theNd:YAG laser system include a power setting of 64.8 watts, a rate ofmarking 5.1 cm/minute, and a frequency of 6 wave peaks per second. Theset distance of the laser system head to the outer surface of the tubingis 18.3 cm (7.2 inches). The indicia is marked so the indicia, with thetubing in the expanded state, exhibits a type-face height in acircumferential direction about the tubing of 2.0 mm.

After marking, the tubing is removed from the core and allowed tosubstantially cold shrinkable back toward the relaxed state. The indiciaon the tubing substantially in the relaxed state is then visuallyobserved by an unaided human eye. The marking is determined to beacceptable if the indicia (exhibiting a type-face height of 2.0 mm) onthe tubing is visually legible by an unaided human eye (i.e., about20/20 vision) from a distance of at least about 36 cm (about 14 inches).

EXAMPLES

The present invention is more particularly described in the followingexamples that are intended as illustrations only, since numerousmodifications and variations within the scope of the present inventionwill be apparent to those skilled in the art. Unless otherwise noted,all parts, percentages, and ratios reported in the following examplesare on a weight basis, and all reagents used in the examples wereobtained, or are available, from general chemical suppliers such as theSigma-Aldrich Chemical Company of Saint Louis, Mo., or may besynthesized by conventional techniques. Also, unless otherwise stated,all performance data included herein for tubing is for tubing cured inan oxygen-free atmosphere. In addition, unless otherwise noted, alltests were performed pursuant to the property analysis andcharacterization procedures described above.

The following compositional abbreviations are used in the followingExamples:

-   DAIKIN G-801: A fluoroelastomer copolymer of vinylidene fluoride and    hexafluoropropylene commercially available from Daikin Industries of    Osaka, Japan.-   DAIKIN G-802: A fluoroelastomer copolymer of vinylidene fluoride and    hexafluoropropylene commercially available from Daikin Industries of    Osaka, Japan.-   AEROSIL® R974: A silane-treated, fumed silica commercially available    from Degussa Company of Parsippany, N.J.-   N-110 Black: A reinforcement-grade carbon black commercially    available from Cabot Corporation, Billerica, Mass.-   N-990 Black: A non-reinforcement-grade carbon black commercially    available from Cabot Corporation, Billerica, Mass.-   TAIC DLC-A: A cross-linking co-agent commercially available from    Natrochem, Inc. of Savannah, Ga.-   Zinc Omadine: A fungicide solution of 65% 2-pyridinethiol-1-oxide,    zinc complex in a paraffinic oil (i.e., Zinc Omadine), commercially    available from Arch Chemicals, Inc. of Cheshire, Conn.-   VAROX® DBPH-50-HP: A 2,5-dim ethyl-2,5-di(t-butylperoxy)hexane    cross-linking agent peroxide curative commercially available from    R.T. Vanderbilt Company of Norwalk, Conn.

The Examples concern cold shrinkable articles of the present inventionin the form of tubing and plaques. The component concentrations of theelastomeric compositions used to form the cold shrinkable articles ofthe Examples are provided in Table 2. The elastomeric compositions ofthe Examples were prepared by combining the components provided in Table2 in a first mixing step, and then mixing these components in a Banburrymixer at between about 20 and 40 revolution-per-minute for about 20minutes at a temperature of about 60° C. The compositions were thenfurther mixed in a 2-roll mixing mill heated to about 50° C. for about 5minutes. The TAIC DLC-A listed in Table 2 was then added to eachcomposition in a second mixing step and the compositions were mixed foran additional 5 minutes. The compositions were then sheeted out inconventional fashion and cooled to the ambient temperature (22-24° C.).

TABLE 2 LMC LTC Components (phr) BT 7 BT 17 BT 18 (Control) (Control)Daikin G-801 100 0 0 0 100 Daikin G-802 0 100 100 100 0 Aerosil R974 5 510 0 0 N-110 Black 10 10 5 0 0 N-990 Black 0 0 0 10 10 Zinc Oxide 2 2 22 2 Zinc Omadine Paste 0.75 0.75 0.75 0.75 0.75 TAIC DLCA 4.2 4.2 4.24.2 4.2 Varox DBPH-50HP 2.5 2.5 2.5 2.5 2.5

The elastomeric compositions of the Examples were extruded into tubinghaving an internal diameter of about 0.25 inches and a wall thickness ofabout 0.18 cm using a ¾-inch extruder with a L/D ratio of 20. Theextrusions were done at a barrel temperature of about 60° C. and a dietemperature between about 30° C. and 60° C. The resulting tubing wascured by peroxide curing. The percent elongation at break and percentpermanent set at room temperature, 130 C, and 150 C were determined.Also, the split resistance at 150° C. for 7 days, stress at break at150° C. was also determined. The results of these tests are included inTables 3 and 4.

TABLE 3 Compound BT 7 BT 17 BT 18 100% 449 451 450 200% 791 796 768 300%1238 1227 1179 Tensile (psi) 3219 3068 3033 Elongation-at-break 618 606619 @ Room Temp Permanent Set (%) 23.3 23.4 22.8

TABLE 4 Permanent Permanent Elongation Elongation Set @ Set @ @ 130 C. @150 C. Composition 130 C. (%) 150 C. (%) (%) (%) LMC n/a n/a 258 214(Control) LTC (Control) n/a n/a 272 242 BT 7 23.4 23.2 513 417 BT 1723.3 23.5 514 423 BT 18 22.6 22.9 468 400

Table 3 provides data at room temperature, and Table 4 provides data atelevated temperatures. The data provided in Tables 3 and 4 illustratesthe expansion capabilities, durability, and tear performance at elevatedtemperatures of cold shrinkable articles formed from the elastomericcompositions of the Examples. The tubing samples of the Examples eachexhibited a percent permanent set of less than 25%. In addition, alltubing samples formed from each of the compositions in BT 7, BT 17, andBT 18 passed the extended split test provided in the Property Analysisand Characterization Procedures section of this document.

In addition, the tubing samples of the Examples all marked well with aYAG laser and passed the laser marking test, when tested pursuant to thelaser-marking procedures including in the Property Analysis andCharacterization Procedures section of this document.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

1. An article of manufacture comprising: a tubular cold shrinkablematerial including: an elastomeric composition, the elastomericcomposition comprising a fluoroelastomer composition, and theelastomeric composition being substantially free of an epichlorohydrincomposition; a filler material, the filler material comprising one orboth of a reinforcement-grade carbon black and silica; and a peroxidecurative wherein the quantity of one or both of a reinforcement-gradecarbon black and silica is in the range of about 10 phr to about 25 phr,and the quantity of peroxide curative is in the range of about 1 phr toabout 6 phr.
 2. The article as defined by claim 1, wherein the quantityof filler material is in the range of about 10 phr to about 25 phr, andwherein the quantity of peroxide curative is in the range of about 1 phrto about 6 phr.
 3. The article as defined by claim 1, wherein thereinforcement-grade carbon black comprises carbon black having anaverage particle size of less than about 40 nm.
 4. The article asdefined by claim 1, wherein silica comprises a silane treated fumedsilica.
 5. The article as defined by claim 1, wherein the tubular coldshrinkable material further comprises a cross-linking agent orcross-linking co-agent.
 6. The article as defined by claim 1, whereinthe article exhibits an elongation greater than 500% and a permanent setless than 25% at room temperature.
 7. The article as defined by claim 1,wherein the article exhibits an elongation greater than 450% and apermanent set less than 25% at 130 degrees Celsius.
 8. The article asdefined by claim 1, wherein the article exhibits an elongation greaterthan 400% and a permanent set less than 25% at 150 degrees Celsius. 9.The article as defined by claim 1, wherein the cold shrinkable materialdoes not tear while being held for seven days in a 200% radiallyexpanded state at 150 degrees Celsius.
 10. The article as defined byclaim 1, further comprising a removable core disposed inside the tubularcold shrinkable material, the removable core supporting the coldshrinkable material in an expanded state.
 11. The article defined byclaim 1, wherein the cold shrinkable material exhibits less than about a25% weight increase when immersed in diesel fuel for 24 hours at atemperature of about 49 degrees Celsius.
 12. The article defined byclaim 1, wherein the cold shrinkable material exhibits less than about a10% weight increase when immersed in hydraulic fluid for 24 hours at atemperature of about 71 degrees Celsius.
 13. The article defined byclaim 1, wherein the cold shrinkable material further comprises anenergy beam absorbent and an energy beam induced indicia charred on anexternal surface of the cold shrinkable material responsive toapplication of a focused energy beam on the energy beam absorbent. 14.The article defined by claim 1, wherein the cold shrinkable materialincludes a plurality of elastomeric members having walls that defineelongate cavities through each elastomeric member, the cavities being incommunication with each other.